Codex/UI color palette

[bodhibuurstede-sys]

Summary

Adds a small shared UI color palette for the colors already reused across SS3D interface code.

Changes

• Keep the existing direct PaletteColors access pattern, but centralize the shared UI colors in one place.
• Add the generic button overlay and text colors that were already being reused by hand.
• Use Color32 for byte-style RGB values so the palette matches Unity's expected channel semantics.
• Add concise documentation for the available colors and how to extend the palette.

Testing

• Reviewed the touched code and documentation statically.
• Not run locally: this Codex environment does not have a Unity editor/runtime available for a full game build.
• Current GitHub Actions run is failing before PR code is checked out. The workflow is pull_request_target and checks out develop, where LockLockerInteraction.cs currently has an unrelated NotImplementedException compile error.

Closes #1377.

[bodhibuurstede-sys]

Quick context for reviewers:

Summary

This PR adds a small centralized UI color palette for shared SS3D interface colors.

Changes

• Kept the existing direct PaletteColors access pattern.
• Added shared text and generic button colors already used by interface styles.
• Switched byte-style RGB values to Color32, since Unity's Color constructor expects normalized 0f..1f channels.
• Added concise documentation for using and extending the palette.

Testing

Not run locally. I do not have a Unity environment available in this Codex session, so this change was reviewed statically only.

Note: the current GitHub Actions run for this PR is failing before PR code is checked out. The workflow is pull_request_target and checks out develop, where LockLockerInteraction.cs currently has an unrelated NotImplementedException compile error.

Addresses #1377.